I don't know___they have passedI don't know___ they have passed t_英语解答

I don't know___they have passed
I don't know___ they have passed the exam
1.what
2.if
3.when
4.where

人气：137 ℃　时间：2020-01-26 06:01:50

解答

2
从句成分完整
表示带有疑问,if此处同whether